Climate Sensitivity Uncertainty and the Need for Energy Without CO 2 Emission

Abstract

The UN Framework Convention on Climate Change calls for “stabilization of greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference with the climate system.” Even if we could determine a “safe” level of interference in the climate system, the sensitivity of global mean temperature to increasing atmospheric CO 2 is known perhaps only to a factor of three or less. Here we show how a factor of three uncertainty in climate sensitivity introduces even greater uncertainty in allowable increases in atmospheric CO 2 concentration and allowable CO 2 emissions. Nevertheless, unless climate sensitivity is low and acceptable amounts of climate change are high, climate stabilization will require a massive transition to CO 2 emission–free energy technologies.